Synergistic insecticidal compositions



United States Patent 2,990,319 SYNERGISTIC INSECTICIDAL COMPOSITIONS Howard A. Jones and John A. Garman, Baltimore, Md., and Berton 'C. Dickinson, Lyndonville, N.Y., assignors to Food Machinery and Chemical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Original application Mar. 24, 1955, Ser. No. 496,596. Divided and this application Nov. 5, 1958, Ser. No. 771,950

6 Claims. (Cl. 167-22) This invention relates broadly to insecticidal compositions, and more particularly to insecticidal compositions containing an organic carbamate acid derivative and 0,0-dimethyl S-( 1,2-dicarbethoxyethyl) dithiophosphate hereinafter referred to as Malathion. More particularly, this invention relates to synergistic insecticidal compositions of these compounds wherein the insecticidal elfectiveness of each component is enhanced by the presence of the other to produce an unexpected combined effect.

When two or more substances in combination show an unexpectedly high activity, as for instance, insecticidal activity, the resulting phenomenon is called synergism. The mechanism of synergism is by no means understood. It is, in fact, quite probable that it difiers with different synergistic combinations. The term synergism can be defined, however, as a cooperative action which is encountered in combinations of two or more biologically active components in which the combined activity of the two components exceeds the sum of the activities of the components when used alone. The insecticidal activity of the mixed components cannot be predicted trom known" values of the individual components, but is unf predictable and depends on the individual activity of neither.

It is an object of this invention to provide insecticidal compositions of enhanced killing power. Another object of this invention is to produce novel compositions containing com-pounds capable of synergizing the knockdown and killing properties of individual toxicants. A further object of this invention is to provide compositions including a relatively toxic phosphorus containing in secticide in which superior insecticidal activity is obtained because of the synergistic effects, but in which the ultimate toxicity to warm-blooded animals is greatly reduced because of the lower concentrations of the ph0sphorous compounds required when used in combination with the relatively less toxic carbamates. Other objects and advantages of the invention will become apparent from the description of the invention set forth below.

According to this invention there are provided synergistic insecticidal compositions comprising 0,0-dimethyl S-(1,2-dicarbethoxyethyl) dithiophosphate, hereinafter called Malathion, and an organic carbamate ester having the following general formula wherein R is selected from the group consisting of ethyl and phenyl radicals and R is selected from the group of hydrogen and ethyl radicals. R is selected from the group consisting of phenyl and methylphenyl and X and X are selected from the group consisting of oxygen and sulfur. These carbamates may be prepared as described in copending application Serial No. 812,113, filed May 11, 1959.

The synergistic insecticidal compositions of this invention may be used on a wide variety of insect and mite species, but are particularly efiective against such insects as the two-spotted spider mite, harlequin bug and Mexican bean beetle. The combinations are highly effective ice and economical to use for such large-scale insecticidal requirements as the control of truck crop, forage crop and orchard insects.

The synergistic compositions of this invention can be formulated as aqueous emulsions, as dry or wettable powders, as solutions or in any other suitable vehicle. The insecticidal compositions can be utilized as sprays, as dusts, as aerosol mixtures, insecticidal coating compositions, and as residues. In general, they can be applied by methods commonly used for control or eradication of insects, mites and the like. Thus these insecticidal compositions can be formulated with solvents, diluents and carrier media, adhesives, spreading, wetting and emulsitying agents and other ingredients.

The relative proportions of the active ingredients as well as inert carriers, solvents, dispersants and the like may vary wide Thus the relative proportion (ratio) of the Malathion to the carbamate ester can range from 20 parts of the former per 1 part of the latter to 1 part of the former per 40 parts of the latter and preferably about 1 part ofthe former to about 2 parts of the latter.

The quantities of the component toxicants in the final insecticidal compositions can range from 0.01% to 25.00% for the Malathion and from 0.05% to 50.00% for the carbarnate, and preferably from 0.10% to 10.00% for the Malathion and from 0.10% to 25.00% for the carbamate.

The procedures of the testing methods are described below. The details of the test experiments including the type of formulation and mode of application or dosing,

.and the species of which served as test subjects DUST TOWER METHOD This general method is described in the following reference, Moore, J. Econ. Ent. 43, No. 2,188- 1950).

The dusting apparatus consists of a vertical glass cylinder, 34 inches high and 8.5 inches in diameter, into which the appropriate dust sample is discharged through a small hole in the center of the cover, by means of a small laboratory duster operating at an air pressure .of 40 p.s.i.g. The duster assembly comprises a 10 ml. beaker, into which the weighed sample is placed, and fitted with a rubber stopper through which pass the air inlet and dust outlet tubes, both of which .are made of 4/; .inch diameter copper tubing. At the outer end of the air inlet tube is a trigger valve that serves as a control for dispensing the dust. The inner end of this tube reaches nearly to the bottom of the beaker. The end of it is sealed but, along the sides, seven 0.032 inch holes are drilled at irregular intervals which serve as air inlets. Such an arrangementcauses pronounced turbulence of the dust and thus insures exhausing the complete sample from the beaker. The dust outlet tube forms an arch from the top of the beaker to the top of the glass dusting tower.

After discharge of the sample into the tower, there is allowed a 2-minute settling time before removal of foliage or insects being treated. A weighed metal plate is placed in the tower each time a test is made, and by weighing the amount of dust deposited on it, it is then possible to calculate the amount applied per acre.

Because of day to-day variations in the results obtained by this test method, comparisons among the individual components and their combinations were made V 3 simultaneously in order to minimize this source of variation.

insect species are as noted below.

Mexican bean beetle.-In tests using this insect, bean foliagewas dusted then infested with fourth instar Mexican bean beetle larvae. These wereallowed to feed for 24 hours, then treated foliage was replaced with untreated. Mortality records were made at 48 hours.

Two-spotted spider mite.-In tests on two-spotted mites, the mites were confined to the upper surfaces of potted bean plants by a Tanglefoot ring. The bean plants were placed in the glass tower and the mites direct-dusted. Mortality readings were taken in 24 hours. Only adult mites were used in determining mortality counts.

Pea aphid.-Pea plants were infested with pea aphids and direct-dusted. Mortality readings were taken at 24 hours.

Harlequin bug.-'The foliage was dusted, then infested with harlequin bugs. Mortality counts were taken in hours.

Squash bug.For test squash leaves were collected in the field and the cut ends of the stem were wrapped in moist cotton. Individual leaves were then placed in 3.5 inch Petri dishes and dusted as described above. Each treated leaf was then infested with 10 last instar squash bug nymphs and the covers of the Petri dishes were replaced. At the end of 24 hours the treated leaves were removed and fresh untreated leaves were introduced into the dishes. Mortality counts 'were taken after the bugs has been on the untreated leaves for 24 hours.

Slight modifications in this test employedfor specific wherein R is selected from the group consisting of ethyl and phenyl radicals, R is selected virom the group of hydrogen and ethyl radicals, R is selected from the group consisting of phenyl and methylphenyl and X and 5 X are selected from the group consisting of oxygen and sulfur, and wherein the dithiophosphate and the carbamate are present in the ratio of about 2 parts of said carbamate per part of said dithiophosphate.

2. Synergistic insecticidal compositions comprising 10 0,0-dimethyl S-(1,2 dicar-hethoxyethyl)dithiophosphate and phenyl N-ethylthiocarhamate, said components being present in the ratio of about 2 parts of said carbamate ester per part of said dithiophosphate.

3. Synergistic insecticidal compositions comprising O,-O-dimethyl S-(1,2 dicarbethoxyethyl) dithiophosphate QO-dimethyl S-(1,2 dicarbethoxyethyl) dithiophosphate and phenyl N,N-diethylthiocarbamate, said components being present in the ratio of about 2 parts of said carbamate ester per .part of said dithiophosphate.

5. Synergistic insecticidal compositions comprising 0,0-dimethyl S-(1,2 dicarbethoxyethyl)dithiophosphate and 3-methylphenyl N-ethylthiocarbamate, said components being present in the ratio of about 2 parts of said carbamate ester per part of said dithiophosphate.

6. The method of killing insects which comprises applying to the insects and their habitat a synergistic insecticidal composition comprising 0,0-dimethyl S-(l,2-

Table 1 B X ll N-GX=R Carbamates Phosphate Rate I 7 Mortality Dust Dust (Lbs-L Test Method Test Subject at24Hrs. R R p R X X Cone. Name Cons. A.)' (Percent) (Per- 7 e 7 cent) cent) Ethyl"--- Hydrogen. Phenyl -O S 0.5 p 11.0 Dust Tower... Two-spottedsplder Mite--. 2 7 Malathiom 0.25 10.7 do 10 Do do d0 0 S 0.5 -do 0.25 8.9 do 92 Pheny do do... S S 0.5 25.2 do 4 Malatht0n 0. 25 29. 5 do 61 Do do do-- S S 0.5 do 0.25 24.6 rln 89 Ethyl- Ethyl"; do 8 O (L5 21.5 (10' 1 Malathlon 0. 25 28.7 do 66 Do do o 's 0 0.5 do- 0.25 17.4 do 100 D0,--- Hydrogen- 3-Methyl O S 0.5 12.0 do 12 phenyl. Malathlon U. 25 1 12. 0 .Do do -do..... 0 S 0.5- do 0.25 10.7 do 81 The results of the data summarized in Table l. demonstrate the marked synergism of the insecticidal compositions of this invention on a number ofinsects.

This application is a division of copending application SerialNo. 496,596, filed March 24, 1955, now abandoned, which is a continuation-in-part of Serial No. 427,374, filed May 3, 1954, now abandoned.

We claim:

1. Synergistic insecticidal compositions comprising 0,0-dimethyl S--( 1,2 dicarbethoxyethyl)dithiophosphate and an organic carbamate ester having the following general formula dicarbethoxyethyl)dithiophosphate and an organic carbamate of the general formula 70 and X and X are selected from the group consisting of oxygen and sulfunand wherein the dithiophosphate and the carbamate are present in the ratio of about two parts of said carbamate per part of said dithiophosphate.

I5 (References on following page) 2,503,390 Ielinek Apr. 11, 1950 OTHER REFERENCES King: US. Dept. Agr., Handbook No. 69, May 1954, pp. 105-108.

Gysin May 25, 1954 5 6 Chemical Age, vol. 63, N0. 1631 (1 950), p. 540. Roark: US. Dept. Agr. Bulletin, E-'344 (May 1935), pp. 2P6.

Sharp: Agr. News Letter, Jan-Feb. 1952, pp. 1-3. Frear: Chemistry of the Pesticides, 3rd ed., January 1955, pp. 73-91. 

6. THE METHOD OF KILLING INSECTS WHICH COMPRISES APPLYING TO THE INSECTS AND THEIR HABITAT A SYNERGISTIC INSECTICIDAL COMPOSITION COMPRISING O,O-DIMETHYL S-(1,2DICARBETHOXYETHYL)DITHIOPHOSPHATE AND AN ORGANIC CARBAMATE OF THE GENERAL FORMULA 